South America: Exceptional water deficits persist in central Brazil

The Big PictureThe forecast through April 2017, as seen in the 12-month map (below), shows widespread water deficits – including large pockets of exceptional deficits (greater than 40 years) – from Brazil’s northern states southward through the center of the country, and deficits trace a path along the Amazon River. Exceptional deficits are also forecast in the Cordillera Real Mountains in western Bolivia, the Gulf of Corcovado in southern Chile, and rivers in southern Argentina.

Forecast BreakdownThe 3-month maps (below) for the same 12-month period clearly illustrate the forecast of a transition in the second half of the period away from widespread exceptional deficits in the first half.

During the next three months, however, (August through October) exceptional water deficits are forecast for much of Brazil north of Rio. Moderate (5 to 10 year) to, primarily, extreme (20 to 40 year) deficits are forecast for: southern Guyana, Suriname, French Guiana, northern Venezuela surrounding Caracas, southern Colombia, Ecuador, Peru, rivers in Bolivia, Chile, the Bermejo River in northern Argentina, southern Argentina including Tierra del Fuego, and the Falkland Islands. Surpluses are forecast to persist in central Argentina and along the Salado River.

In November and December the extent of exceptional water deficits in Brazil is forecast to diminish though extreme to exceptional deficits will persist along the Amazon River and in the northeastern states of Amapá and Maranhão. From November through January moderate deficits are expected to continue to emerge throughout Colombia, and in western and southern Venezuela, Guyana, Suriname, French Guiana, Ecuador, and Peru. Moderate deficits are also forecast to emerge in southern Rio Grande do Sul, Brazil.

In Chile deficits are forecast to persist though with diminished severity during this period. Likewise, deficits in some parts of southern Argentine will diminish, except along the Rios Negro, Chubut, and Deseado.

(It should be noted that forecast skill declines with longer lead times.)

Many analyses reported in ISciences-authored blog posts are based on data generated by the ISciences Water Security Indicator Model (WSIM). Other sources, if used, are referenced in footnotes accompanying individual posts. WSIM is a validated capability that produces monthly reports on current and forecast global freshwater surpluses and deficits with lead times of 1-9 months at 0.5°x0.5° resolution. This capability has been in continuous operation since April 2011 and has proven to provide reliable forecasts of emerging water security concerns in that time-frame. WSIM has the ability to assess the impacts of water anomalies on people, agriculture, and electricity generation. Detailed data, customized visualizations, and reports are available for purchase.

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